Front Cover
 Table of Contents
 Table 1. Spacing of plants and...
 Table 2. Spray chart

Title: Blackberry production in Florida
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00084306/00001
 Material Information
Title: Blackberry production in Florida
Series Title: Blackberry production in Florida
Physical Description: Book
Creator: Shoemaker, J. S.
Publisher: Agricultural Extension Service, Institute of Food and Agricultural Sciences, University of Florida
 Record Information
Bibliographic ID: UF00084306
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 228504024

Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7 (MULTIPLE)
        Page 8
        Page 9 (MULTIPLE)
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15 (MULTIPLE)
        Page 16 (MULTIPLE)
        Page 17
        Page 18
    Table 1. Spacing of plants and posts
        Page 19
    Table 2. Spray chart
        Page 20
Full Text


in florida

Agricultural Extension Service
Institute of Food and Agricultural Science
University of Florida, Gainesville

MARCH 1966



Varieties .- ..-....-- ---------------------------- ----- 3

Pollination ...-----------------------...------------ 4

Propagating the Plants .------- ----------------------- 5

Selecting the Site -----.........--- ------ ----------------- 6

Setting and Spacing the Plants .------- -- ---.- ----- 7

Trellising and Training _.------- ---. ---------.......--------- 7

Handling Canes after Harvest ......-------------.---. 9

Controlling Weeds ...- - --------------------------- ------ 9

Fertilizing ..------. .----- --. --------- 10

Irrigation _--..-. ...-- -- --------------.----- 11

Yield ..-- ----------- -- 13

Harvesting .---. ---------- ... ........ 14

Destroying Unwanted Blackberry Plants ---------- 15
Life of Planting .--.--......-------.--------. ........ 15

Costs --- - ---_----- ------ ------ ---- --------- 16

Controlling Pests -... ---------------.----------- 16

Diseases ...----------------------------- - 16

Insects --------------------- --- 18

Table 1-Spacing of Plants & Posts 19

Table 2-Spray Chart ............------ ------- 20

Credit: Writing of the sections on irrigation, insects, and diseases was coordinated
with D. S. Harrison, Associate Agricultural Engineer, J. E. Brogdon, Entomolo-
gist, and R. S. Mullin, Pathologist, Agricultural Extension Service, University
of Florida.

Blackberry Production

In Florida
J. S. Shoemaker and R. M. Davis'

Commercial blackberry produc-
tion has become a reality in Florida
recently through introduction of
adapted varieties.
These new varieties produce high
yields of large, attractive berries
which have been shipped success-
fully to fresh fruit markets in
northern cities, to Europe, and to
local markets. The commercial im-
portance of blackberries in Florida
arises from the fact that Florida

producers, using the new varieties,
can reach the market earlier than
producers in other regions.
At present Florida production is
aimed at the fresh fruit market;
in the future, processing may be-
come another large outlet per-
haps the major outlet for the crop.
Cultivated acreage has increased
substantially in recent years, and
estimates of up to 2,000 acres have
been projected by 1975.


Northern blackberry varieties
do not thrive in Florida because
they require a long duration of
winter chilling temperatures (ac-
cumulated hours below 45" to 55

F.), and in some instances, because
of the prolonged heat and warm
soil during summer. This is also
generally true for the 'Boysen' and
similar types of berries.

Horticulturist, Florida Agricultural Experiment Station; Assistant
Horticulturist, Agricultural Extension Service, Department of Fruit Crops,
University of Florida, Gainesville, Florida.
Figure 1. A three month old, ten acre planting of trailing varieties.

The best varieties for Florida
are: (1) the earlier fruiting trail-
ing type 'Flordagrand,' and its pol-
linators such as 'Oklawaha' -

which also produce highly desir-
able berries; and (2) the later
fruiting semi-erect type, 'Brazos'.
See Rosette (double blossom dis-


A blackberry is composed of
many drupelets, each of which de-
velops from a single pistil. To
obtain a perfect, well-formed berry
most or all of the pistils must be
effectively pollinated by s o m e
"mass" method such as by honey-
For effective cross-pollination of
trailing-type varieties (which are
not self pollinating) hives of
honeybees should be placed in or
near the plantings just before
The hybrid trailing-type varie-
ties released at Gainesville from
a cross of 'Regal Ness' X the native
Rubus trivialis either: (a) do not
set any fruit from their own pollen,
or (b) are self-fruitful to a certain
degree but produce well-formed
berries when cross-pollinated. Both
types produce viable pollen which
causes berries to set on other close-
ly related varieties.
'Flordagrand,' the main new va-
riety, depends on roughly a 50-50
interplanting with pollinator plants
for good production of large, well-
formed berries. A simple 50-50
proportion can be obtained by
planting alternate rows of 'Florda-
grand' and a single pollinator va-
riety. The 'Oklawaha' was intro-
duced for this purpose and has
been highly effective.
It may be desirable to interplant

Figure 2. The difference in size of
berries may be due to frost damage,
imperfect pollination, or the fruiting
habit of blackberries.

'Flordagrand' with another variety
in addition to the earlier-maturing
'Oklawaha' for longer fruiting and
complete cross-pollination. One
possibility is a variety nearly ready
for naming at this printing. The
variety still being tested is also

self-fruitful and therefore must be
planted with a cross-pollinator.
Such a planting would contain 50
percent 'Floragrand' and 25 per-
cent each 'Oklawaha' and the third
variety. These pollinator rows

should also be alternated.
The semi-erect 'Brazos,' does
not require cross-pollination, but
blooms too late to be an effective
pollinator for the hybrid trailing-
type varieties grown in Florida.

Propagating the Plants

Where blackberries are to be
grown in or adjacent to citrus, use
only those plants grown on a cer-
tified, nematode f r e e site or in
sterilized potting media. Any pro-
ducer growing plants for commer-
cial plantings should have his site
certified nematode-free by the Di-
vision of Plant Industry, Florida
Department of Agriculture. Be-
cause of the high incidence of bur-
rowing nematodes in the state it
is desirable to use only leafy stem
cuttings for propagating material.
Leafy Stem Cuttings. Most
nursery plants in Florida have been
propagated by leafy stem cuttings
under mist. Thousands of cuttings

can be obtained by this method
from an established planting, us-
ing the new canes while their
growth is still soft. However, a
large number of cuttings taken
from plants too late in the year
may adversely affect the succeed-
ing year's crop.
Make cuttings 4 to 5 inches long,
and insert them top end up and
just deep enough to stand firmly
erect in the rooting medium. Im-
perfect drainage results in failure
with cuttings that are inserted
deeply into the medium. Do not
allow cut propagation material to
dry out in handling.
Perlite and/or peat mixed with

Figure 3. A typical propagating bed for leafy stem cuttings.

16 NwINUN1

I- u t-

coarse builder's sand provides a
well drained and aerated rooting
medium. In 5 to 6 weeks, the root-
ed cuttings can be removed from
the mist and lined out in nursery
rows where they can be irrigated.
As an alternative method, place
each cutting individually into a
perforated plastic bag or other
suitable container filled with the
medium for rooting under mist.
When rooted, these cuttings can
be used for direct field planting.
Root Cuttings.-Another method
of propagating blackberries is by
root cuttings. Select roots, prefer-
ably as thick as a lead pencil or
somewhat larger, and cut into
pieces 31 to 6 inches long. Lay
these cuttings horizontally 6 to 8
inches apart in nursery rows and
cover them with 2 to 3 inches of

soil. Dig the cuttings after roots
have formed, a fair amount of
top growth has been made, and
conditions are favorable for plant-
Planting bare-root pieces direct-
ly in permanent quarters in the
field sometimes results in slow or
poor top growth and uneven vigor
the first year, but a good stand is
usually obtained in time (see irri-
Sucker Transplants. The semi-
erect 'Brazos' develops plants by
suckering from the roots and in
this way tends to fill in spaces
between the plants originally set
in the row. Suckers may also de-
velop along the sides of the rows.
In established plantings it is pos-
sible to dig many suckers for trans-
planting without affecting the crop.

Selecting the Site

The blackberry is adapted to a
wide range of soils, providing they
are well drained. On mineral soils,
a slightly acid range pH 5.5 to
pH 6.5 should provide optimum
growing conditions. Little infor-
mation is available for peat and
muck soils, but blackberries have
been grown with some success on
muck which tested as low as pH
4.7 (see calcium).
Returns from a high-yield plant-
ing justify using good land for
blackberries. Select a site with
good air drainage and frost pro-
tection. Frost protection at or near
bloom is probably the most impor-
tant single factor of the site in
relation to yield.
On many sites, frost hazard be-

gins as soon as buds have swollen,
and can continue to affect even
berries that have set. Open blos-
soms show injury at about 26'F.
and young berries at a minimum
of 28F. The pistils of open flowers
may be killed by frost while the
petals escape, so that the blossoms
appear normal but do not set fruit.
The fruit-producing canes may be
weakened at 20F. to 24"F.
The trailing-type 'Oklawaha' and
'Flordagrand' bloom earlier than
the semi-erect 'Brazos'. The earlier
bloom results in an earlier crop,
which is usually an advantage on
the fresh-fruit market. On the
same site, the two types seldom
overlap in bloom, and picking may
have been in progress for 3 weeks

on the trailing varieties before the
peak of bloom occurs on 'Brazos.'
The later bloom of 'Brazos' may

enable this variety to escape frost
damage that could reduce the crop
on the others in some years.

Setting and Spacing the Plants

The cool months are best for
setting blackberry plants, but they
may be planted all during the year.
If planting is done during warm,
dry weather, irrigation is always
With trailing varieties, canes ex-
tend several feet from the plant
center so that the growth of ad-
jacent plants becomes intermin-
gled. There are several advantages
to comparatively wide spacing in
the row:
Greater opportunity to distribute
longer canes on the trellis (such
canes may produce larger berries
than shorter, more branched
Fewer plants required to set an
Fewer posts required.
Fewer "hills" of canes to cut
back to ground level after harvest.
More complete spray coverage
for pest control.
Easier and more thorough pick-

Higher percentage of marketable
fresh fruit.
There are several methods of
trellising for trailing varieties. A
strong 3-wire system is often con-
structed (see upright trellis).
Plants may be spaced, for example,
8, 9 or 10 feet apart in the row
with 3 plants between posts that
are 24, 27 or 30 feet apart, respec-
There are many possible varia-
tions for the number of plants
per acre, spacing in the row, be-
tween rows, and between posts and
in number of posts (Table 1). The
spacing between rows is often 10
to 12 feet but optimum spacing
depends largely on the equipment
to be used.
Set plants of the semi-erect
'Brazos' 4 feet apart in the row.
When set directly in the field, space
bare-root cuttings slightly closer
than nursery plants.

Trellising and Training

Trailing Type.-For easier pick-
ing and tillage, and cleaner berries,
canes must be supported off the
ground. The usual method is to
train the canes on a wire trellis
erected shortly before or soon after
planting. The cost of a wire trellis
is largely offset by its advantages.
A number of trellising methods are
used by different growers; only

the leading method is described
The upright trellis, with the top
horizontal wire (No. 9 galvanized)
about 5 feet high and two other
horizontal wires (No. 10 or 11)
spaced 18 inches apart, permits
good distribution of canes and
their branches. Such strong wire
should last for the life of the plant-

,-' *. *....... ... -- ^ 1 ^

Figur 4. nri
Figue 4.Tingnwcns oa pigttels
I -

Figure 4. Tying new canes to an upright trellis.

ing (12 to 15 years). Although
initially cheaper, lighter wire does
not last as long (see Handling
Canes After Harvest).
Steel posts, although compara-
tively expensive initially, make ex-
cellent intermediate posts. They
are more durable and easier to
place in the ground than wooden
posts. Steel posts do not need
grounding against lightning dam-
age, but it is wise to ground some
of the wooden posts in each row
since lightning running along the
wires may kill plants. Wooden
posts commonly used as intermedi-
ates are at least 3 inches thick,
about 61/2 feet long, and placed 11/2
feet into the ground.
Wooden end-posts should be
placed deeper into the ground than
intermediate posts, and should be
well braced. They should be 7 to

71/' feet long to insure deeper
placement, and at least 6 inches
thick to support a long-row trellis.
Pressure-treating wooden posts
(with chlorophenol or creosote)
prolongs their life and makes it
possible to use somewhat lighter
ones. Avoid planting close to fresh-
ly treated posts.
It is best first to tie a framework
of canes on the trellis, twisting
some around the wire. Later de-
veloping canes are drooped, but not
bent sharply, over the wires and
canes already there, and tied when
Semi-Erect Type. In training
'Brazos', after the canes have been
cut back to ground level, top the
terminals of new canes when the
desired height (4 feet) has been
reached. Cut off the terminal 3 to
4 inches below the tip to cause

wide-angled branching and dis-
courage further upright growth
which may result when only the
extreme tip is pinched off.
Remove all branches originating
near the ground. Shorten the re-
maining branches in late summer,
or whenever necessary, to keep
them out of the row middles dur-
ing the growing season. This prun-
ing, in addition to heading back

branches to a length of 2 feet or
shorter during the winter, may
eliminate the need for a trellis.
However, one wire running 3
feet or so high along the row, in
combination with pruning, helps
maintain more erect bushes and
keeps branches in bounds. Using
2 wires, when placed either one
above the other or at the same
level, may be advantageous.

Handling Canes after Harvest

Each year after harvest, remove
all the canes of both trailing and
semi-erect varieties that bore fruit
that year. Fruiting canes die after
harvest, are of no further use in
the planting, and may harbor
The general procedure is to cut
back to ground level both old and
new canes soon after harvest,
either by hand or with a mower.
A supply of new canes has plenty
of time to develop in the long
growing season from harvest to
cold weather.
The old fruiting canes which
were tied, wound around, or droop-
ed over wires are cut loose. The
brush which results should be
gathered up with forks, hauled out
of the planting, and burned.

At best, removal of old canes is
a time-consuming job. Two other
procedures have been used by some
growers with trailing-type plants.
In one, the canes are allowed to dry
on the trellis, then both old and
new canes are burned in place
(completely or down to the lowest
wire) with a quick passage of
flame. On the other hand some
growers use lighter wire, (e.g.,
Nos. 12 to 14 instead of the strong-
er Nos. 9 to 11) and pull out the
wire or cut it at intervals and
roll or push the canes (including
cut wire) out to the end of the row.
Advocates of this latter scheme, or
some modification of it, claim it is
cheaper to buy new wire yearly
than to use a permanent trellis of
heavier wire.

Controlling Weeds

It is imperative to control weeds
and grass in the planting. It is also
important to cultivate shallow
since deep cultivation destroys
some of the root system and re-
tards growth.
Hoeing is especially important

as a means of encouraging a good
start for a new planting; but it is
also important to hoe near plants
in established plantings.
Plantings are more likely to es-
cape frost damage to blossoms and
developing berries if the ground


Figure 5. An example of clean cultivation in the planting.

is firm and bare. A thick stand
of weeds or other vegetation hin-
ders accumulation of heat in the
soil during the day, and reduces
release of soil heat at night. Frost
hazard is also greater if a planting
is disked just prior to prevailing
conditions which may result in
frost; dry, loose soil checks con-
duction and liberation of heat from
the soil.
Herbicides. The control effect
of herbicides in weedy plantings is
temporary, and some materials
that control weeds and certain
grasses may damage the semi-
evergreen type of blackberry
plants. Not enough work has been
conducted on herbicides as cultural
tools for blackberries to outline a
good program; but, they show con-
siderable promise. It is a good prac-
tice with herbicides to treat a

small area on a trial basis. Always
follow directions on the label.
Simazine, a pre-emergent herbi-
cide, probably has been used in
more blackberry plantings in Flor-
ida than any other herbicide.
Apply it to bare soil prior to weed
growth or after cultivation at the
rate of 4 pounds active ingredient
per acre. With bearing plants apply
before bud break or after harvest.
Do not apply when fruit is present.
Since part of the selective action
depends on where the chemical is
placed, do not cultivate the treated
area after herbicide application un-
til the action of the chemical has
lessened considerably.
Cultivation could seriously affect
blackberries if the herbicide is
mixed with soil in the root zone
and could also reduce effective
weed control.


Excessive amounts of fertilizer,
besides increasing the cost, may

do more harm than good. Too much
fertilizer may, for example, "burn"

"-' d.~i-


the roots (dehydration due to ex-
cessive fertilizer salt concentra-
tion). Fertilizing will not offset a
poor stand of plants, imperfect
drainage, inadequate pollination,
and other limiting factors; it
should accompany other good cul-
tural practices. Results vary with
conditions in different plantings.
The complete effect of a fertilizer
does not appear the year it is ap-
plied since canes produced one year
bear fruit the succeeding year.
Until more information becomes
available, the following fertiliza-
tion procedures are suggested:
First Year: About 3 weeks after
planting apply 1/5-pound per plant
of a mixed fertilizer (e.g., 8-8-8,
containing minor elements) in a
uniform band 8 to 12 inches wide
around each plant. Keep the band
6 to 12 inches from the plants.
If the planting was made during
the late fall or winter no additional
fertilizer need be applied until late
February or early March when 1/2-
pound of a mixed fertilizer should
be applied. Repeat at 8-week inter-

vals or as needed until early Sep-
Succeeding Years: Three appli-
cations- the first in late February
or early March, the second just
after the canes have been removed
in June, and the third in late
August or early September are
recommended after the first year.
A mixed fertilizer, (e.g. 8-8-8 con-
taining the minor elements) is
recommended at rates which en-
sure 100 pounds of actual nitrogen
per acre per year. Keep the ma-
terial 18 to 24 inches from the
Exact requirements have not
been determined, but a good cal-
cium supply in the soil may pro-
mote firmer berries. Normally the
calcium supply will be adequate if
the soil is limed as required to
maintain the recommended soil pH
range of 5.5 to 6.5. High calcic
limestone would ordinarily be used
for this purpose, but when the
magnesium supply is limited a
dolomitic limestone will supply
both calcium and magnesium.


Because of variations in fre-
quency and amount of rainfall,
irrigation appears necessary for
successful blackberry production
in Florida. The type of system,
well size, irrigation frequency,
rates, and timing need further
There are 3 good systems for
irrigating blackberries:
1. Permanent overhead, using
medium pressure sprinklers of 45
to 55 pounds/square inch (psi)

spaced 60' to 70' or closer. PVC
plastic underground pipe is sug-
gested. With the pump centrally
located the entire acreage can be
irrigated at one time, as shown in
Figure 7 (sample plan for 3 acre
block) ; or it can be irrigated in 5
sets also shown in Figure 7.
2. Permanent overhead system
using half-circle mist nozzles (low
pressure 10 to 20 psi) spaced 10
feet apart in each row. This re-
quires polyethelyne tubing for each

row. The advantage of this system
is smaller droplets; but of course,
it takes longer to apply one inch
of water.
Precipitation rates for perman-
ent systems should be from .10 to
.20 inches per hour (net). Figure
irrigation frequency at 70 to 80
percent for daytime operation.
3. A portable pipe system con-
sisting of medium pressure rotary
sprinklers spaced as described in
the first type of system. This sys-
tem requires movement of pipe for
each irrigation setting. Its initial
cost is lower due to the small
amount of portable aluminum pipe
necessary to do the job. Applica-
tion rates in portable systems
should be from .20 to .35 inches
per hour. This requires a double-
nozzle sprinkler.
Well Size is determined by the
quality and rate of water desired.

'-' 'f

*71 .. ,

Figure 6. A well designed permanent
overhead irrigation system using med-
ium pressure sprinklers.

A 6-inch well produces a maximum
of about 400 GPM whereas a 4-inch
well cannot be expected to produce
over about 50 GPM at 65 psi dis-
charge pressure and 60-foot lift.

Ssoo r
t- o e- WELL
$1so arM & oS PIt DISCIARGE

] 1 z2 I 2' 1CYCE
I |- ------- -- I-I 4 WELL
-I Se SPM a 65 PSI

S1 0 .177'/HK OR O- I'/WR

8602, SKINNERt S-715,

How Much Water to Apply de-
pends on root zone depth, soil
water-holding capacity and the
water to be replaced at each irriga-
tion interval.
Mature blackberry plants have
an effective root zone of approxi-
mately 3 feet. Good blackberry soil
has a maximum water capacity
range of .50 to .90 inches per foot-
depth. Irrigation is necessary when
50 percent of the water has been
depleted in the root zone. There-
fore, using .70-inches per foot as
an average water-holding capacity,
the irrigation water should be sup-
plied when .70-inch/ft. depth x 3
ft. (depth root zone) x .50 deple-
tion = 1.00 inches per application.
Heavier soils require about 1.25
inches; for lighter soils add only
.75 inch.
In general, 1.00 inch net per ap-
plication is sufficient. This would
require a gross application of
about 1.25 inches per application.
Irrigation is needed soon after
planting and during the dry periods
of late spring and early summer.
The amount of lapsed time between
irrigations depends on the water-
use rate by the plant and the soil's
water-holding capacity. The water-
use rate increases as daily mean
temperature and length of day in-

During May and June irrigation
frequency may be about every 5
days, but during February and
March it may be every 12 to 14
days or longer. On windy days
with low humidity, more supple-
mental water is needed.
What Time of Day to Apply. -
Turn on sprinklers when winds are
lowest. Do not operate systems
during bloom, except in late after-
noon or evening. Irrigating when
bees are active as pollinators may
result in less fruit set.
During the fruiting season, irri-
gate each block immediately after
picking so ripe fruit is not damag-
ed by falling droplets of water.
Plan irrigation for a week or so
before harvest so subsequent ap-
plications fall immediately after
picking. Water may soften berries
and cause rot, and splashing water
may cause dirty berries near the
ground. Placing strips of straw or
other mulch material along the
rows may help avoid dirty fruit.
Irrigation soon after cutting
back the canes to ground level en-
courages vigorous growth which
otherwise may be slow starting -
especially during prolonged dry
weather. On some sites, early fall
irrigation may be essential.


In the trailing varieties, yield
basically depends on the degree
of effective cross-pollination. Under
good cultural and weather condi-
tions, plants have produced over
20 pints each; a few growers have

reported over 40 pints per plant
for both the trailing type and for
the semi-erect 'Brazos' in small
plantings. Commercially, a grower
can exceed 12,000 pints per acre,
or 1,000 twelve-pint trays.


The harvest season of early
('Oklawaha') and early midseason
('Flordagrand') trailing varieties
extends from March into June,
varying in different years and lo-
cations. 'Brazos' ripens later, thus
prolonging the harvest season of
cultivated blackberries 3 weeks in
a given area or planting.
Varying with many factors, in
the trailing varieties the total
soluble solids (sugar) has averag-
ed 8.5 percent, the total titratible
acidity 1.5 percent, and the solids/
acid ratio of 6.5. Corresponding
figures for 'Brazos' are 8.6 solids,
1.2 acid, and 7.1 ratio. The berries
are very large and attractive in
appearance, which is an important
feature in marketing.
Blackberries should become com-

pletely black in external color be-
fore they are picked. Leave reddish
(immature) berries on the plant
for a later picking. Discard over-
ripe and damaged berries. The
same plants are usually picked
every second day for fresh-fruit
market. Pick only dry berries and
keep them dry, otherwise they
soon decay. Do not wash black-
berries for fresh market, or im-
merse them in water and then
repack. Blackberries turn reddish
if exposed to sun after picking;
place them in shade as soon as
picked and keep them cool.
Take blackberries to market in
the pint containers in which they
have been picked. Keep containers
clean. Do any sorting into separate
boxes, while picking. A tray or

Figure 8. A typical well filled flat of large, attractive berries ready for market.
a C <--

flat widely used for marketing con-
sists of a single layer of 12 pints
of berries, 6 pints on each side of
a central divider. Fill each pint
box sufficiently to allow for some
settling without crushing.
Because of the thorny or prickly
nature of blackberry canes, pickers
should use rubber gloves with the
fingers cut off. When plants are
bearing a heavy crop, a picker can
average a pint of berries in less
than 5 minutes, and often can pick
two 12-pint trays in an hour. The
grower should insist not only on
clean picking (gathering all ripe
fruit) but also on an attractive
product for the fresh-fruit market.
Pickers are usually paid for
"piece work," either on a per pint
or per flat basis.
Some growers allow customers
to do the picking and charge a
reduced price for the berries pick-
ed. It is possible to build up a
program of this kind to an extent

4,.-. k I

Figure 9. For easier picking of trail-
ing varieties, just before harvest begins,
remove or cut back interfering new
canes along the sides of the rows as
well as new growth which is extending
outward from the plant.
that obtaining pickers is not a
Mechanical harvesting of Florida
blackberries is still in the develop-
mental and trial stage. The hope,
particularly in large plantings for
processing, is for more rapid har-
vesting and reduced hand labor
requirements. Efficient m a c h i n e
harvesting requires a special meth-
od of training the plants.

Destroying Unwanted Blackberry Plants

When a grower desires to com-
pletely kill blackberry plants, 2,4,5-
T (2, 4, 5 trichlorophenoxyacetic
acid) spray is used. Cut canes back
to about a foot high during active
growth. Use a 2,4,5-T solution at
1,000 ppm active ingredient in two
sprays a week or so apart. The

material will be translocated to the
roots, thus killing them, eliminat-
ing further sucker growth and
completely killing the plant. A
stronger solution would kill the top
of the plant too quickly to allow
translocation to the roots. Avoid
drift of 2,4,5-T to desirable plants.
Use the amine form.

Life of Planting
A blackberry planting should have fruited are replaced by new
live for 12 to 15 years, and produce canes. Plants may live longer than
10 good crops during this time, 12 to 15 years but the per-acre
depending on such factors as the yield may drop because of decreas-
site, frost, and cultural practices. ed vigor. See Rosette (double
From year to year, canes which blossom).


Establishing a planting. Some
growers have an advantage over
others in already owning most
items required such as cleared
land, an irrigation system, and the
necessary machines and equipment
in connection with other farming
operations. Thus, their main ex-
penses the first year may be for
plants, posts and wire, and for
labor in planting, trellising, con-
trolling weeds, and irrigating. This
may total $300 to $500 an acre.
A more frequent first-year cost
is $600 to $750 an acre for a com-
mercial planting. A higher initial
investment for more permanent
equipment and materials may re-
sult in a lower annual maintenance
In a bearing year. Some grow-
ers obtain and deserve a higher
price than others for their berries.
Although this is due sometimes
to superior salesmanship of the
grower himself, in berry auctions
quality, as judged by size and ap-
pearance of the berries, is a prime
consideration. For continued large
sales to distant markets, chain

markets, and other fresh fruit
sources, a grower must produce
large, attractive berries.
Picking and marketing may
amount to 25 to 40 percent of total
yearly production cost. The re-
maining 60 to 75 percent of cost
in bearing years is mostly for
controlling weeds, handling canes
before and after harvest, fertiliz-
ing and irrigating.
The cost of establishing a trail-
ing-type planting is usually higher
than for 'Brazos,' largely because
of higher posts, more wire, and
trellising. However, the life ex-
pectancy for high yields may be
several years longer for the trail-
ing-type than for 'Brazos.'
Some berries are produced a
year after planting. The amount
of crop will depend on when the
plants are set and their subsequent
growth. A vigorous growth the
first year may result in a medium
crop the succeeding year. By the
third year the grower should be
obtaining near maximum yields
and a good annual return on his

Controlling Pests
The "Big 4" factors in control- grower must consider residue tol-
ling pests by spraying are thor- erances and waiting period requir-
oughness, timely application, use ed between the last spray and
harvest. Spray only with materials
of the proper material, and suit- hr o w
that have been registered and
able strength of solution, cleared for use on blackberries in
Near and during harvest the Florida.
(See also spray schedule)
Leaf spot shows on the foliage center. It occurs in most black-
as dark red spots with a whitish berry plantings and tends to weak-

en the plants. Good cultural care,
including cutting back both old
and new canes to ground level (and
burning all prunings) after har-
vest, plus sufficient moisture and
fertility tend to offset any exhaus-
tive effect from this fungus dis-
ease. However, spraying with a
fungicide may be necessary in
many plantings to avoid a heavy
build-up of the disease.
Anthracnose is a fungus disease
causing lesions (grayish spots with
a purplish brown margin) on the
canes and fruit stems, and some
deforming, browning, and wither-
ing of the berries. The same prac-
tices as with leaf spot lessen the
weakening effect of anthracnose.
Rosette (double blossom) dam-
age has been negligible in well
cared-for plantings of trailing va-
rieties. They are highly resistant
to the disease in Florida, and only
an occasional infected twig is seen
in plantings.
However, rosette can heavily in-
fect 'Brazos' plants in Florida. A
mildly infected new 'Brazos' plant-

Figure 10. Witches'-broom and ab-
normal blossoms caused by Rosette with
a normal, healthy blossom in the center.

ing usually produces a high yield
for several years, but when the
infection becomes severe, vigor and
yield decline. When and to what
extent this decline may occur is not
known at the present time.
Rosette is caused by a fungus
(Cercosporella rubi). It is readily
recognized at two stages: (1)
witches'-broom stage, in which
multiple, bunchy shoots appear on
semidormant canes; (2) an abnor-
mal flowering stage (hence the
name double blossom) which fol-
lows the first stage and occurs
mostly on shoots which first show-
ed, or still show, witches'-broom.
Flowers on infected shoots are
often more numerous than usual
and may be elongated with the
sepals extending as leaflike struc-
tures. Petals may be deep pink,
and the twisted, deformed flowers
turn brown or fail to unfold or to
develop fruit.
The disease follows a set cycle.
In spring, spores produced on the
blossoms first infect young buds on
new canes and later the flower
buds. Infected canes show no ex-
ternal evidence of the disease in
summer. In winter and early spring
infected buds show witches'-broom
and, later abnormal flowers. Spores
produced on the stamens and pis-
tils reinfect undeveloped buds of
the new canes.
Cutting back to ground level
and burning both the old and new
canes soon after harvest is a good
practice (see Handling Canes After
Harvest). Using root cuttings,
taken from and planted on nema-
tode-free sites, rather than leafy

stem cuttings or sucker trans-
plants may help to avoid the dis-
ease or lengthen the time before
occurrence of heavy infection.
There is not enough evidence at
present for a firm recommendation
for spray control of rosette (dou-

ble blossom) in 'Brazos'. If, how-
ever, high production in a 'Brazos'
planting is to be maintained for as
many years as the trailing type, it
may be necessary to emphasize a
control program in which spraying
plays a major role.

(See also Spray Schedule)

Thrips are tiny insects with
rasping and sucking mouth parts.
By abrasive action, they cause the
skin of drupelets to become thin
enough that the juice can be sucked
out. They may cause damage to
blossoms, reduce both the total
crop and percentage of marketable
fruit, and are objectionable on
harvested berries.
Spraying with an insecticide
either during bloom or harvest
presents problems and prevents
use of certain materials. Bees may
be poisoned if spraying is done
during bloom while they are work-
ing the flowers. This reduces the
strength of the colonies and in
turn, the amount of cross-pollina-
Thrips can be seen in developing
flowers before they open. Not all
blackberry flowers open on the
same day, and harvesting may con-
tinue for 3 weeks or more. Spray
with malathion to control thrips
just before the earliest flowers
open, and once or twice more (in
late afternoon or evening) during
the next 10 to 15 days. Any spray-
ing near, and especially during, the
harvest season must comply with
pesticidal restrictions (see Table

Spider mites are small, but can
be seen with the aid of a hand lens.
Multiplication is rapid in dry wea-
ther. They live, lay their eggs, and
spin delicate webs on the under-
sides of leaves. They feed by pierc-
ing the epidermis of the leaf to
draw the liquid contents from the
cells. When infestation is severe
the leaves appear sickly, somewhat
harsh, and rusty. Heavy rains have
a checking effect on spider mites.
Stink bugs are shield-shaped,
broad, and rather large in the adult
stage. Their gland secretions cause
a bad taste in infested berries.
They insert their needlelike beak
into the berries, suck the juice, and
may deform the berries. There are
several stages of nymphs.
Foliage caterpillars and several
other kinds of chewing insects may
destroy a considerable part of the
foliage on a plant in severe infes-
tations. Larvae of the strawberry
leaf roller may cause webbing of
the leaves.
Termites may cause damage to
plants that are mulched with saw-
dust, unless the soil is treated with
4 lbs active chlordane per acre or
2 Ibs active aldrin per acre worked
into soil at time of planting.

TABLE 1.-Spacing of plants and posts in row and number of plants and posts per acre *

2 Plants Between Posts 3 Plants Between Posts 4 Plants Between Posts
Spacing of Feet Feet Posts Feet Feet Posts Feet Feet Posts
Plants in Plants Between Between per Between Between per Between Between per
Row, feet per Acre Posts Rows Acre Posts Rows Acre Posts Rows Acre

4 1089 8 10 545 12 10 363 16 10 272
908 8 12 454 12 12 303 16 12 227

5 870 10 10 435 15 10 290 20 10 218
726 10 12 363 15 12 242 20 12 182

6 726 12 10 363 18 10 242 24 10 182
605 12 12 302 18 12 202 24 12 152

7 622 14 10 311 21 10 207 28 10 156
518 14 12 259 21 12 173 28 12 130

8 544 16 10 272 24 10 181 32 10 136
453 16 12 227 24 12 151 32 12 114

9 484 18 10 242 27 10 161 36 10 121
403 18 12 202 27 12 135 36 12 101

10 435 20 10 218 30 10 145 40 10 109
363 20 12 182 30 12 121 40 12 91

The number of end posts varies with different lengths of rows per acre.

TABLE 2.-Spraying to control Blackberry Pests

Spray Pests Amount per 100 Remarks and
Period Controlled Material Gallons of Water Waiting Period (in Parenthesis)

1. Postharvest Leaf Spot Neutral copper (1) 3 lbs. To avoid severe infection, especially dur-
to Cold Anthracnose, (48-53%) ing periods of wet weather, spray every
Weather Rosette (Double or Zineb (1) 2 lbs. 2 to 4 weeks or as needed the first year
Blossom) or Maneb (1) 1%/ lbs. and during the growing season after cut-
ting the canes to ground level in fruiting
2. Semi-Dormant Rosette As above Slightly stronger In an attempt to check rosette at first
Plants (Double Blossom) than in No. 1 indication of witches'-broom stage.
3. Spring Flush Diseases as Neutral copper (1) 3 lbs. (No time limit)
of Growth to in No. 1 or Zineb (1) 2 lbs. (14 days)
First Bloom or Maneb (1) 1z lbs. Do not use after bloom
Chewing Insects Carbaryl (Sevin) 11 lbs.
80% sprayable) (7 days) When needed
or DDT 2 Ibs. (50% WP) Do not apply after fruit begins to form.
4. Bloom to End Diseases as in Neutral copper 3 lbs. (No time limit)
of Harvest No. 1; Fruit Rots, Captan 4 Ibs. (40% WP) (No time limit)
Thrips and
Plant Bugs Malathion 1 qt. 57% EC) (3) (1 day) See thrips in text.
5. Special Spider Malathion As above (1 day) Most serious in
Spray Mites or Kelthane 1 qt. 18.5% EC (2 days) dry weather.






better results may be obtained by alternating materials.

(4) The tolerances and waiting periods apply mostly to Spray Period No. 4
Residue tolerances are as follows: Carbaryl (12.0 ppm), Captan (100.0 ppm), Copper (exempt), Demeton (Sytox)
(0.0 ppm), DDT (7.0 ppm), Guthion (2.0 ppm), Kelthane (5.0 ppm), Maneb (0.0 ppm), Malathion (8.0 ppm),
"arathion (1.0 ppm), Zineb (7.0 ppm). Demeton, Guthion and Parathion are not recommended for home gardens
Id b -''- o"ly by a tir- -sator.

Instead of using the same material for repeat sprays.
Wettable powder
Emulsifiable concentrate.

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